How to easily build concentric curved tubes to make layered tubes?
I say you try this as a solution:
Add a cylinder. Delete the top and bottom faces of it. Give it a solidify modifier. Duplicate it and scale it down by locking the Z axis until it's boundaries fit in the inner boundaries of the biger cylinder.
Once you are happy with the thickness and scale apply the solidify modifier. And then hit Ctrl+A to apply scale on both the objects. Then select both of them and hit Ctrl+J to join. Then rotate them along the X axis by 90 degrees. Then go to Object&gt;Set Origin&gt;Origin to Geometry. Then apply the rotation. Then add in an array modifier. Set the X and Z offset to 0 and the Y offset to 1. The count on the Array Modifier will change the lenght of your object. Then add in a path.
Rotate the curve on the Z axis by -270 degrees. Then add in a curve modifier on your object and select that path. Then scale that path to be as long as your object. Now if you go into edit mode on your path you can play with the verticies of your path and your mesh will be deformed.